我对onMapReady有疑问。当我传递这样的地址时：
LatLng myAddressCoordinates = getLocationFromAddress("Piazza Ferretto Mestre");
地图和标记都可以正常工作，但是当我传递从 textview 读取的地址时：
LatLng myAddressCoordinates = getLocationFromAddress(TVStringa.getText().toString());
我抛出这个异常：
java.lang.IllegalArgumentException: latlng cannot be null - a position is required.
at com.google.android.gms.maps.model.MarkerOptions.position(Unknown Source:6)
at com.example.alex.alfa0.schedaIntervento.onMapReady(schedaIntervento.java:199)
at com.google.android.gms.maps.zzaj.zza(Unknown Source:7)
at com.google.android.gms.maps.internal.zzaq.onTransact(Unknown Source:38)
at android.os.Binder.transact(Binder.java:627)
at gl.b(:com.google.android.gms.DynamiteModulesB@11580470:20)
at com.google.android.gms.maps.internal.bf.a(:com.google.android.gms.DynamiteModulesB@11580470:5)
at com.google.maps.api.android.lib6.impl.bc.run(:com.google.android.gms.DynamiteModulesB@11580470:5)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
第 199 行：
mapView.addMarker(new MarkerOptions().position(myAddressCoordinates).title(Indirizzo));
我的 getLocationFromAddress 方法：
public LatLng getLocationFromAddress(String strAddress) {
/**
* A class for handling geocoding and reverse geocoding.
* Geocoding is the process of transforming a street address or other description of a location into a (latitude, longitude) coordinate.
* Reverse geocoding is the process of transforming a (latitude, longitude) coordinate into a (partial) address.
* The amount of detail in a reverse geocoded location description may vary,
* for example one might contain the full street address of the closest building,
* while another might contain only a city name and postal code.
*
* See more at: https://developer.android.com/reference/android/location/Geocoder.html
*/
Geocoder coder = new Geocoder(this);
//A list because of getFromLocationName will return a list of address depending on how many result I want
List<Address> address;
LatLng p1 = null;
try {
/**
* List<Address> getFromLocationName (String locationName, int maxResults) *
* | locationName | String: | a user-supplied description of a location |
* | maxResults | int: |max number of results to return. Smaller numbers (1 to 5) are recommended |
* See more at: https://developer.android.com/reference/android/location/Geocoder.html
*/
address = coder.getFromLocationName(strAddress, 2);
if (address == null) {
return null;
} //I take just the first result even if I've got list of 5 different LAT;LNG results
Address location = address.get(0);
location.getLatitude();
location.getLongitude();
p1 = new LatLng(location.getLatitude(), location.getLongitude());
return p1;
} catch (Exception e) {
e.printStackTrace();
}
return p1;
}
完整的类代码：
public class schedaIntervento extends AppCompatActivity implements OnMapReadyCallback {
TextView TVNome, TVID, TVNomeP, TVCognome, TVVia, TVNumero, TVCitta, TVCap, TVChiamata, TVOperatore, TVCodice, TVData, TVStringa;
String Nomee, Indirizzo;
GoogleMap mapView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_scheda_intervento);
TVNome = findViewById(R.id.TVNome);
TVID = findViewById(R.id.TVID);
TVNomeP = findViewById(R.id.TVNomeP);
TVCognome = findViewById(R.id.TVCognome);
TVVia=findViewById(R.id.TVVia);
TVNumero = findViewById(R.id.TVNumero);
TVCitta = findViewById(R.id.TVCitta);
TVCap = findViewById(R.id.TVCap);
TVChiamata = findViewById(R.id.TVChiamata);
TVOperatore = findViewById(R.id.TVOperatore);
TVCodice = findViewById(R.id.TVCodice);
TVData = findViewById(R.id.TVData);
TVStringa = findViewById(R.id.TVStringa);
Nomee = getUsername();
String url = "myurlforapi";
getJSON(url);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.mapView);
mapFragment.getMapAsync( this);
}
private String getUsername() {
Intent i = getIntent();
String j = i.getStringExtra("Username");
TVNome.setText(j);
return j;
}
private void getJSON(final String urlWebService) {
class GetJSON extends AsyncTask<Void, Void, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
try {
loadIntoTextView(s);
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
protected String doInBackground(Void... voids) {
try {
URL url = new URL(urlWebService);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("POST");
con.setDoInput(true);
con.setDoOutput(true);
Uri.Builder builder = new Uri.Builder()
.appendQueryParameter("Username", Nomee);
String query = builder.build().getEncodedQuery();
OutputStream os = con.getOutputStream();
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(os, "UTF-8"));
writer.write(query);
writer.flush();
writer.close();
os.close();
con.connect();
StringBuilder sb = new StringBuilder();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
String json;
while ((json = bufferedReader.readLine()) != null) {
sb.append(json + "\n");
}
return sb.toString().trim();
} catch (Exception e) {
return null;
}
}
}
GetJSON getJSON = new GetJSON();
getJSON.execute();
}
private void loadIntoTextView(String json) throws JSONException {
JSONArray jsonArray = new JSONArray(json);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject obj = jsonArray.getJSONObject(i);
TVNomeP.setText(obj.getString("Nome"));
TVCognome.setText(obj.getString("Cognome"));
TVVia.setText(obj.getString("Via"));
TVNumero.setText(obj.getString("Numero"));
TVCitta.setText(obj.getString("Citta"));
TVCap.setText(obj.getString("CAP"));
TVChiamata.setText(obj.getString("Motivo_chiamata"));
TVOperatore.setText(obj.getString("Operatore"));
TVCodice.setText(obj.getString("codice"));
TVData.setText(obj.getString("Data_di_nascita"));
Indirizzo = "Via " + TVVia.getText().toString() + " " + TVNumero.getText().toString() + " " + TVCitta.getText().toString();
TVStringa.setText(Indirizzo);
}
}
public LatLng getLocationFromAddress(String strAddress) {
/**
* A class for handling geocoding and reverse geocoding.
* Geocoding is the process of transforming a street address or other description of a location into a (latitude, longitude) coordinate.
* Reverse geocoding is the process of transforming a (latitude, longitude) coordinate into a (partial) address.
* The amount of detail in a reverse geocoded location description may vary,
* for example one might contain the full street address of the closest building,
* while another might contain only a city name and postal code.
*
* See more at: https://developer.android.com/reference/android/location/Geocoder.html
*/
Geocoder coder = new Geocoder(this);
//A list because of getFromLocationName will return a list of address depending on how many result I want
List<Address> address;
LatLng p1 = null;
try {
/**
* List<Address> getFromLocationName (String locationName, int maxResults) *
* | locationName | String: | a user-supplied description of a location |
* | maxResults | int: |max number of results to return. Smaller numbers (1 to 5) are recommended |
* See more at: https://developer.android.com/reference/android/location/Geocoder.html
*/
address = coder.getFromLocationName(strAddress, 2);
if (address == null) {
return null;
} //I take just the first result even if I've got list of 5 different LAT;LNG results
Address location = address.get(0);
location.getLatitude();
location.getLongitude();
p1 = new LatLng(location.getLatitude(), location.getLongitude());
return p1;
} catch (Exception e) {
e.printStackTrace();
}
return p1;
}
@Override
public void onBackPressed() {
super.onBackPressed();
this.finish();
}
@Override
public void onMapReady(GoogleMap googleMap) {
this.mapView = googleMap;
/*LatLng sydney = new LatLng(-33.852, 151.211);
googleMap.addMarker(new MarkerOptions().position(sydney)
.title("Marker in Sydney"));
googleMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));*/
LatLng myAddressCoordinates = getLocationFromAddress(TVStringa.getText().toString());
//LatLng myAddressCoordinates = getLocationFromAddress("Piazza Ferretto Mestre");
mapView.addMarker(new MarkerOptions().position(myAddressCoordinates).title(Indirizzo));
mapView.moveCamera(CameraUpdateFactory.newLatLngZoom(myAddressCoordinates, 16));
}
}